//alert("第一次使用JavaScript程序！");
//console.log("hello");
//alert(2688/164);
//alert(264*(6+134)/4-46);
//alert(5452 < 5);
//alert(5452 > 5);
//alert(5452 == 5);
//alert("hello");
//alert('hello');
//alert("123");
//alert('123');
//alert(123);
//alert("123" + "123");
//alert("123" + '123');
//alert("123" + 123);
//alert(123 + 123);
//console.log(10 === "10");
//console.log(10 === '10');
//console.log("220+230="+220+230);
//if (22 > 30){
//    alert("22大于30")
//}else{
//    alert("22小于30")
//}
//var num1=22;
//var num2=33;
//alert(num1 + num2);
//alert(num1 - num2);
//var temp = num1;
//
//num1 = num2;
//num2 = temp;
//
//console.log(num1);
//console.log(num2);
//console.log(temp);
//if (prompt("请输入你的姓名")=="admin"){
//    alert("您好：管理员");
//}else {
//    alert("您好：用户");
//}
//var time = new Date();
//console.log(time);
//console.log(time.getHours());
//var h = time.getHours();
//console.log(h);
//if (h <19){
//    alert("白天好");
//}else{
//    alert("晚上好");
//}
//function sum(a,b){
//    var c = a + b;
//    return c;
//}
//alert(sum(22,33));
//function num(){
//    alert(100);
//}
//num();
//function num(a){
//    alert(a);
//}
//num(300);
//function num(a,b,c){
//    alert(a * b / c - b * c);
//}
//num(5,2,1);
//var footer1 = document.getElementById("footer");
//console.log(document.getElementById("footer"));
//console.log(document.getElementById("footer").innerHTML);
//footer1.innerHTML = 4;
//
//var header = document.querySelector("header");
//header.innerHTML = 5;
//
//var main = document.querySelector(".main");
//main.innerHTML = 6;
//
//var footer2 = document.querySelector("#footer");
//footer2.innerHTML = 7;

function color(a){
    document.querySelector("body").style.background = a;
}
function bgzdy(z){
    color(z.value);
}







